A 71-Year-Old Man with Gastric Cancer

Case: A 71-Year-Old Man With HER2+ Gastric Cancer

Initial Presentation

• A 71-year-old man complained of a 3-month history of abdominal pain and bloating, a sensation of fullness
• PMH: HTN, medically controlled; colonoscopy at age 53 was unremarkable; no family history of cancer
• PE: patient appeared tired, abdominal distention; otherwise unremarkable
  
  

Clinical Workup

• Labs: Hb 9.7 g/dL, plt 111 x 109/L; other lab values WNL
• Upper endoscopy with biopsy: showed an ulcerative lesion 5.8 cm mass in the cardia of the stomach; biopsy confirmed gastric adenocarcinoma
• CT of chest/abdomen/pelvis confirmed a 5.8 cm lesion with indistinct margins in the cardia of the stomach; 2 suspicious hepatic lesions
• EUS: gastric cancer lesion confirmed invasion of the muscularis propria
• Mutational testing: MSI high, PD-L1 0%, HER2 3+ by IHC
• Stage IV gastric adenocarcinoma; ECOG 2
  
  

Treatment

• He was started on XELOX/CAPOX + trastuzumab
  • Dose reduced due to grade 2 diarrhea; unable to control after 4 cycles; discontinued treatment
• Treatment initiated with a pembrolizumab
  • After 24-months of treatment without progression of disease pembrolizumab was discontinued
• The patient was started on trastuzumab deruxtecan; repeat HER2 expression testing was not indicated